The correct answer is: A. wooden sleepers.
Pandrol clips are a type of fastening system used to secure rails to sleepers. They are made of steel and have a U-shaped profile. The clips are attached to the sleepers with bolts, and the rails are then placed in the clips and secured with nuts.
Pandrol clips are not suitable for use with wooden sleepers because the wood is not strong enough to withstand the forces exerted by the clips. The clips can also damage the wood, making it more susceptible to rot and decay.
Pandrol clips can be used with concrete sleepers, CST-9 sleepers, and steel trough sleepers. These materials are all strong enough to withstand the forces exerted by the clips, and they are not damaged by the clips.
Here is a brief explanation of each option:
- Option A: Wooden sleepers are made of wood, which is not strong enough to withstand the forces exerted by Pandrol clips. The clips can also damage the wood, making it more susceptible to rot and decay.
- Option B: Concrete sleepers are made of concrete, which is strong enough to withstand the forces exerted by Pandrol clips. Concrete sleepers are also not damaged by the clips.
- Option C: CST-9 sleepers are made of a composite material that is strong enough to withstand the forces exerted by Pandrol clips. CST-9 sleepers are also not damaged by the clips.
- Option D: Steel trough sleepers are made of steel, which is strong enough to withstand the forces exerted by Pandrol clips. Steel trough sleepers are also not damaged by the clips.